Michael Miles reports.
A floating platform held the key to security upgrades of valve towers at impound reservoirs – built more than 100 years ago.
The pontoon solution at Leigh and Luxhay reservoirs sees Wessex Water conclude a rigorously managed 3-year programme of security upgrades in line with regulatory standards.
Groundworks for the high security Ultrasecure mesh building included landscaping, concreting and installation of a specially designed former base system.
While enhancing security, Wessex Water’s asset upgrades include operational features to safeguard personnel.
Environmental consideration formed part of Wessex Water’s solution, including the provision of bat apertures in tunnel door systems.
Retrofitting security systems to Victorian water engineering can pose challenges. Pioneering in their day, these ageing structures now rely on 21st century ingenuity to extend their service life and bring them in line with modern security and operational standards.
This is certainly true of a recent Wessex Water project to enhance the protection of two impounding reservoirs in Somerset, constructed in the late 1800s.
Coordinated by Wessex Water project manager Steve Lanzon, the contract involved the design and build of physical and electronic protection measures, compliant with current government guidelines and standards. Central to this has been the engineering of high security access systems for valve towers sited within the reservoirs.
The access solutions have met tough challenges, both in their design and water-borne installation in compliance with construction, safety and hygiene standards. In addition, site logistics needed careful planning to minimise the impact of construction and mobilisation of materials within the sensitive environment.
Differences in the construction of the towers were a further complication.
Luxhay reservoir is served by a tunnel which required a high security door with egress for bats, and a modular mesh cage building to further secure surface access. A high security escape hatch was also specified for an emergency exit point at the top of the tower. Access to Leigh reservoir is via a single entry point on top, necessitating the installation of a secure access cover enclosed within a high security cage as an additional deterrent.
Best Value Solutions
Technocover undertook design, manufacture and installation of the high security access equipment. The company offers a concept-to-commission ‘Total Service’ approach to water security projects, focused on delivering best value solutions from its LPCB approved range or bespoke service. This includes site survey, security consultation, in-house design and manufacture, system installation, life-time maintenance of products, and, in the case of Wessex’ impounding reservoirs, acting as principal contractor.
Integral to the site solution was a pontoon, transporting materials and providing an 8m square work platform around the water-locked towers. As well as supporting up to eight operatives at any one time, it needed to carry a mechanical lifter with 350kg lift capacity for moving components into position.
Using proprietary grid modules, Technocover designed the floating platform for a 1 tonne maximum load capacity over 4m square and a half tonne point load within the same footprint.
It was 90% preassembled bank side and used to transport tools, product components and lifting equipment to the towers accompanied by a safety boat. The final platform section was then added as the pontoon was fixed into position ready for work.
Groundworks for the modular mesh cage building system also required special attention.
Following a structural survey, Technocover designed and manufactured a special galvanised steel former system for concrete infill on site to protect an existing staircase from any loadings. This offered a faster method of construction and, therefore, the lowest cost solution.
‘Right First Time’
To ensure programme efficiency, Technocover worked closely with Wessex Water at design and approval stage. This allowed detailed fine-tuning of product design, installation and site logistics for a ‘right first time’ outcome.
Joe Hughes, Wessex Water’s site manager, said: “The product solutions needed to offer an element of flexibility while complying with current legislation, being fit-for-purpose and, as far as possible, visually unobtrusive.
“Technocover refined design details to accommodate all these and other issues including planning permissions, land-owner views, and environmental considerations such as the bat aperture in access doorways.”
The comprehensive planning paid off, even when the April build programme was hit by unexpectedly wintry conditions.
“Work needed to meet the agreed deadline, and weather conditions couldn’t have been worse, with snow, wind, rain, short daylight hours and extreme cold,” said Mr Hughes. “It left Technocover with a vast amount of work to complete in little over two weeks of actual site time, but they managed to achieve it.”
He added: “Any water-borne job in such adverse conditions needs careful workforce supervision and health and safety management. Technocover’s safety manager was present throughout to supervise and react on the spot to any issues.”
In working with restricted operations, the installation team were required to observe a particularly complex set of safe working and hygiene practices. These included strict procedures for chlorination of pontoon components, safety boats and equipment, as well as complying with safety guidelines for working on water, at height and from a floating work platform.
Technocover also mobilised a range of lifting equipment, HIABs, trailers, safety boat, utility vehicles and welfare units from its own fleet to support construction and safely move parts and equipment over rough terrain. The company undertook all necessary method statements, devising safe systems of work and running the whole operation to CDM regulations.
Electronic control and monitoring of the access points was carried out by Wessex Fire and Security using innovative technology. The system alerts Wessex Water’s control room of attempted breach of access, distinguishing them from being impacts such as rainfall, wind, birds or branches.
‘Turnkey’ solutions like this from a total service security specialist offer numerous benefits to water clients, their site agents and contracting partners. In providing a rigorously managed, one-stop response to security upgrades, the full service supplier can significantly ease the burden of delivering a very specialised and critical element of asset protection. This is certainly an attractive proposition as water companies step up the risk management of ageing assets, extending longevity and improving their resilience.
Ian Blair, Head of Health, Safety & Security at Wessex Water, said: “Enhancing security at the two reservoirs has been a challenge requiring careful planning and close liaison between all parties. The innovative security and installation solutions delivered by Technocover have improved both site security and employee safety at these sites.”
He added: “This work comes at the end of a three year project for Wessex Water that completes security upgrades at our water supply sites in accordance with regulatory standards that will increase the security of supply to our customers and their confidence in the drinking water quality.”
For further information telephone 01938 555511 or E-mail: email@example.com
Michael Miles is MD of Technocover, the leading specialist in LPCB approved and bespoke physical security solutions for water engineering.